Classification of Organisms Why Classify To study the

Classification of Organisms • Why Classify? • To study the great diversity of life, organisms must be divided into manageable groups. The system must have 2 important features:

• Universally accepted – everyone can interpreted • Place organisms in groups that make biological sense – insects vs. fishes

• Early scientific names were very long and descriptive (20 or more words) • Swedish botanist, Carolus Linnaeus, developed a system still use today – binomial nomenclature • Each organism have a 2 part scientific name Genus: Acer Species: Rubrum RED MAPLE

The science of naming organisms and assigning them to groups is called taxonomy.

• Kingdom: Animalia • Phylum: Chordata (they share a spine and nervous system) • Class: mammalia (warm-blooded, hair, produce milk) • Order: Carnivora (meat-eaters) • Family: Ursidae (bears) • Genus: Ursus • Species: arctos (Brown bear)

Human (Homo sapiens) • Kingdom Animalia • Phylum Chordata • Class Mammalia • Order Primates • Family Hominidae • Genus Homo • Species sapiens

Fruit Fly (Drosophila melanogaster) • Kingdom Animalia • Phylum Arthropoda • Class Insecta • Order Diptera • Family Drosophilidae • Genus Drosophila • Species melanogaster

• Several acronym mnemonics have been made for these: • King Phillip called out for good soup • Kings Play Chess On Funny Green Squares

Phylogenetic Trees -- Classification lists the unique characters of each taxon and is ideally designed to reflect phylogeny —the evolutionary history of a group of organisms. • Phylogenetic tree is a diagram that indicates common ancestors and lines of descent.

Phylogenetic Trees • A primitive character is present in the common ancestor and in all members of a group.

Classification and Phylogeny

Table 22. 1 Molecular Data and the Evolutionary Relationships of Vertebrates Mader: Biology 8 th Ed.

Biochemical Differences

Traditional versus Cladistic View

Constructing a Cladogram

Constructing a Cladogram